Conventional containers such as vials, which hold drugs, are sealed pathways to mouths with sufficiently sterilized rubber plugs in order to store and carry the drugs in hygienic conditions. They are provided with lock means to the rubber plugs around the mouths so as to prevent these rubber plugs from loosening up and the conditioner from deterioration caused by air inflow through a gap between the rubber plugs and the mouths.
As with the lock means described above, the applicant of the present invention has disclosed the cap which comprises a close-fastening ring detachably formed on an upper portion of a crown-like member surrounding a rubber plug in the corresponding document 1. It is used in such a manner that the close-fastening ring is cut off from the crown-like member and put on the outer periphery of the member by pressing the ring towards the mouth.
Description of corresponding document 1: Japanese Unexamined Patent Publication No. 09-278051 (see FIG. 6 and FIG. 7).
For containers of drug in particular, there are many cases in which the adhesion between the mouth portion of the container and the rubber cap is set up at a high degree. For this reason, it is difficult to detach the rubber plug, while it is easy to detach the aforementioned conventional cap (lock means); and this has caused inconveniences in carrying out the medical activities.